Testing of biological materials may include the use of color-based reaction testing, whereby a test pad is exposed to urine, blood, saliva, feces or sweat. For example, urinalysis is an array of tests performed on urine and one of the most common methods of medical diagnosis. Urinalysis is used as a screening and/or diagnostic tool by virtue of being able to detect substances or cellular material in the urine associated with different metabolic and kidney disorders. For example, substances such as protein or glucose will begin to appear in the urine before patients are aware that they may have a problem.
Color-based reaction testing, such as urinalysis, is typically performed using “dipsticks,” which are strips of plastic or sturdy paper to which a series of reagent test pads have been affixed, as shown in FIG. 1A. Each reagent test pad on the dipstick 100 is chemically treated with a compound that is known to change color in the presence of particular reactants. For example, in the context of urinalysis, the dipstick 100 will typically include reagent pads for detecting or measuring glucose, bilirubin, ketone (acetoacetic acid), specific gravity, blood, pH, protein, urobilinogen, nitrite and leukocytes in urine.
The process of testing biological materials involves first submerging or otherwise exposing the aforementioned dipsticks and affixed reagent pads to a subject's urine, saliva, blood, feces, sweat. If the urine contains quantities of the particular reactants, one or more of the reagent test pads will change color as a result. The magnitude of the change is further indicative of the amount of the particular reactants that are present.
Urinalysis dipsticks, for example, are typically accompanied with a reference color chart, such as chart 110 shown in FIG. 1B, for evaluating test pad color changes following exposure to urine. As shown in FIG. 1B, the typical reference color chart 110 will include a spectrum of possible colors associated with each corresponding reagent pad on the dipstick, thereby allowing a healthcare provider to “read” the test results with the naked eye. However, manually comparing different shades of a given color can be difficult to perform and lead to unacceptably lower accuracy. Thus, it is preferable for healthcare providers to use a specialized electronic reader to eliminate the subjectivity of visual color interpretation, thereby making the color-based reaction testing process simpler and more reliable. Such electronic readers are highly-calibrated devices that typically use either reflectance photometers or charge coupled device (CCD) image sensors. Specifically, since the process of accurately capturing and comparing color is so vital to the process, the image-capturing environment has to be precisely controlled across different tests since even slight variations in ambient light, test pad location or image-capturing angle can lead to inaccurate results. Moreover, there is even substantial variation across different CCD sensors meaning that each reader has to be individually calibrated.
The problem is that such electronic readers are typically too expensive for most smaller laboratories to use. Moreover, since these readers have to be so highly calibrated, they are closed, non-mobile devices, meaning that the resulting test data is not readily portable and that the actual test has to be performed wherever the electronic reader happens to be located.
Accordingly, there is a need to provide an alternative approach to reading color-based reaction test results of such biological materials that is more accurate and precise than manual reading, yet also cost effective.